Fabrication of mechanically enhanced superhydrophobic surface using nanosecond laser-based high-throughput surface nanostructuring (nHSN)

Abstract

Abstract In this work, we conduct a systematic experimental investigation of surface integrity for steel and aluminum alloys processed via nanosecond laser-based high-throughput surface nanostructuring (nHSN) process. nHSN surface morphology and surface chemistry are first experimentally characterized, and the results show that surface nanostructure with proper surface chemistry is generated due to the combined effect of chemical etching and attachment of functional groups of low surface energy. Desired surface wetting behavior is achieved using a proper silane reagent during the nHSN chemical immersion treatment phase, while surface nanostructure can be finely modulated by adjusting the laser processing parameters. nHSN nanostructures with fluorosilane chemistry exhibit strong capability to repel water, leading to superhydrophobicity achieved on two important engineering metal alloys, namely steel and aluminium alloys. It is further experimentally demonstrated that the microhardness and anti-corrosion performance of the nHSN surface can be significantly enhanced compared with the untreated surface, indicating that the nHSN process is very effective for enhancing the mechanical strength and corrosion resistance of these important metal alloys. These results show that nHSN simultaneously creates random nanostructures, attains desirable surface chemistry and enhances surface integrity over large-area metal alloy surfaces.